Mold



1.1. EARLY.

MOLD.

APPLICATION FILED FEB. 7, I921.

1,412,392. Patented Apr. 11, 1922.

Inventor.

Jbhn J Earlqy,

W (M by 3W0.

umren STATES PATENT OFFICE.

MOLD.

Specification of Letters Patent.

Patented Apr. 11, 1922.

Application filed February 7, 1921. Serial No. 443,188.

To all whom. it may concern Be it known that I, JOHN J. EARLEY, a citizen of the United States, and resident of Washington, District of Columbia, have invented certain new and useful Improvements in Molds, of which the following is a specification.

My present invention relates to molds, and more specifically to those of the type commonly known as non-absorptive. These molds or forms are of the class used for the shaping of articles from concrete or the like.

Molds or forms for concrete may be generally classed as absorptive or non-absorptive with respect to their ability to draw water from the plastic concrete placed within them.

When absorptive molds draw water from the mass of concrete, they draw with it the finest of the solid particles contained in the mass and deposit them on the surface of the mold. This process displaces the larger particles from the surface of the mold to just that degree in which the finer particles are attracted. Inversely, a non-absorptive mold does not disturb the normal consistency of the concrete nor the arrangement of the solid particles contained in it. In the manufacture of concrete products from concrete such as that under consideration, it is very desirable that no change should be made in the plastic mass by any action of the mold.

Molds for concrete work are made from various materials which, when it is so desired, are rendered non-absorptive'to water by various methods which may be briefly reviewed as follows:

1. Molds made of sand are generally made non-absorptive by saturation with water.

2. Molds made of wood are generally made non-absorptive by a coating of oil or paint or by the application of a sheet metal covering.

3. Molds made of metal are considered non-absorptive.

4. Molds made of gypsum or similar plastic material have a high degree of absorption and are generally rendered non-absorptive by saturation with water or oil, or by the application of a viscous coating, such as paint, shellac or the like. On such molds, a coating of this type is not generally satisfactory when multiple copies are to be made in the same mold, because the mold itself does not attain great strength and the viscous coating is not sufiiciently strong to protect it from damages from attrition, due to the impact of the concrete while being filled into it.

However, for concrete products of complicated form, molds made with gypsum or similar materials are for reasons of economy and facility very desirable, therefore a method for rendering them non-absorptive and for protecting them from damage is valuable.

I have developed such a method by applying to the surface of the mold made of gypsum or similar materials, a membrane which is both waterproof and protective. Such a membrane is found among the metal foils, waterproofed fabric such as paper, cloth or the like.

My invention consists in the novel construction, arrangement and combination of parts hereinafter described and illustrated in the accompanying drawing, in which the figure is a perspective View of a sectionof mold lined according to my invention. Referring now to the drawing, the mold of plastic material is shown at 1, provided with a waterproof protective coating 2 of metal foil, waterproofed paper, cloth or the like. This coating is attached to. the mold by means of a highly viscous binder, such as shellac or the like. By utilizing a binder of this type, puckering of the lining is eliminated and worn portions thereof may be readily removed and a new surface applied without defacing the mold proper. A portion of the lining is shown turned back from the mold, which clearly illustrates this replacement feature.

What I claim is:

l. A mold made of gypsum or the like provided with a waterproofprotective interior coating in sheet form.

2. A mold made of plastic material having an interior coating of metallic foil.

3. A mold made of plastic material having a waterproof protective interior coating in sheet form attached thereto by means of a viscous binder.

4. A porous mold provided with a water proof protective interior coating attached to said mold by means of shellac.

In testimony whereof, I aflix my signature.

JOHN J. EAR-LE1. 

